It is not permitted to perform dangerous actions on machines or systems in the safety-related environment from just any location. Until now it has only been possible to operate these systems at stationary points or using wired devices. However, these limiting factors are obviated by wireless technology. To fulfill safety engineering requirements, areas must be technically defined and an unambiguous assignment made to these areas. It is already known for suitable effective ranges to be defined, within which a machine is operated wirelessly using a control device, the effective ranges being delimited by one or more RFID transponders. Safety requirements are imposed on the use of such control devices in connection with the function of the effective ranges.